#include<stdio.h>
#include<iostream>
#include<algorithm>
#include<vector>
#include<string>
#include<utility>
#include<map>
#include<set>
#include<queue>
#include<stack>
#include<functional>
#include<math.h>
#include<random>
#include <bitset>
using namespace std;
#define N (1000000000+7)
//#define N 998244353
#define INF 1e16
typedef long long ll;
typedef pair<int,int> P;
typedef pair<int,P> Q;
typedef vector<ll> vec;
typedef vector<vec> mat;

const int inf = (int)1e9; 

int main(void){
	ll x,y,h;
	cin>>x>>y>>h;
	x = 1000*x;
	y = 1000*y;
	ll ans = 0;
	ll t = 1LL;
	ll s = 1LL;
	if(x>y)swap(x,y);
	while(x>h*t){
		ans++;
		t*=4LL;
		s*=2LL;
	}
	h*=s;
	t = 1LL;
	while(y>h*t){
		ans++;
		t*=4LL;
	}
	cout<<ans<<endl;
	return 0;
}